N-acetyl cysteine (NAC) is a specially modified form of the dietary amino acid cysteine that has various proposed uses.

Nitrates such as nitroglycerin lose some of their effectiveness over time. According to some studies,
1,2
but not all,
3,4
the supplement N-acetyl cysteine might help these drugs work better. However, there's a catch: the combination of NAC and nitroglycerin appears to cause severe headaches.
5,6

Taking NAC with nitroglycerin may be beneficial in some cases. However, unpleasant side effects probably limit the use of this combination.

Note:
Angina is too serious a disease for self-treatment. If you have angina, do not take any supplement except on a physician’s advice.

Vitamin C may help prevent the development of tolerance to nitrate medications such as nitroglycerin.
According to a double-blind study of 48 individuals, use of vitamin C at a dose of 2000 mg three times daily helped maintain the effectiveness of nitroglycerin.
10
These findings are supported by other studies as well.
9,13,14

Note:
Angina is too serious a disease for self-treatment. If you have angina, do not take any supplement except on a physician’s advice.

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Ghio S, de Servi S, Perotti R, et al. Different susceptibility to the development of nitroglycerin tolerance in the arterial and venous circulation in humans. Effects of N-acetylcysteine administration.
Circulation.
1992;86:798–802.

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